Every day people become more dependent on computers to help with both work and leisure activities. However, computers operate in a digital domain that requires discrete states to be identified in order for information to be processed. This is contrary to humans who function in a distinctly analog manner where occurrences are never completely black or white, but always seem to be in between shades of gray. Thus, a central distinction between digital and analog is that digital requires discrete states that are disjunct over time (e.g., distinct levels) while analog is continuous over time. As humans naturally operate in an analog fashion, computing technology has evolved to alleviate difficulties associated with interfacing humans to computers (e.g., digital computing interfaces) caused by the aforementioned temporal distinctions.
A key set is one of the earliest human-machine interface devices, traditionally utilized in a typewriter. Unfortunately, not everyone who wants to utilize a computer knows how to type. This limits the number of computer users who could adequately utilize computing technology. One solution was to introduce a graphical user interface that allowed a user to select pictures from a computing monitor to make the computer do a task. Thus, control of the computing system was typically achieved with a pointing and selecting device known as a “mouse.” This permitted a greater number of people to utilize computing technology without having to learn to use a keyboard. Although these types of devices made employing computing technology easier, it is still not as intuitive as handwriting and drawing.
Technology first focused on attempting to input existing typewritten or typeset information into computers. Scanners or optical imagers were used, at first, to “digitize” pictures (e.g., input images into a computing system). Once images could be digitized into a computing system, it followed that printed or typeset material should be able to be digitized also. However, an image of a scanned page cannot be manipulated as text or symbols after it is brought into a computing system because it is not “recognized” by the system, i.e., the system does not understand the page. The characters and words are “pictures” and not actually editable text or symbols. To overcome this limitation for text, optical character recognition (OCR) technology was developed to utilize scanning technology to digitize text as an editable page. This technology worked reasonably well if a particular text font was utilized that allowed the OCR software to translate a scanned image into editable text.
Subsequently, OCR technology reached an accuracy level where it seemed practical to attempt to utilize it to recognize handwriting. The problem with this approach is that existing OCR technology was tuned to recognize limited or finite choices of possible types of fonts in a linear sequence (i.e., a line of text). Thus, it could “recognize” a character by comparing it to a database of pre-existing fonts. If a font was incoherent, the OCR technology would return strange or “non-existing” characters, indicating that it did not recognize the text. Handwriting proved to be an even more extreme case of this problem. When a person writes, their own particular style shows through in their penmanship. Signatures are used, due to this uniqueness, in legal documents because they distinguish a person from everyone else. Thus, by its very nature, handwriting has infinite forms even for the same character. Obviously, storing every conceivable form of handwriting for a particular character would prove impossible. Other means needed to be achieved to make handwriting recognition a reality.
As is typical, users continued to demand more from their systems. Thus, just recognizing a page eventually was not enough to satisfy all users. Although the digital age has made some aspects of working with documents easier, many users prefer to use traditional means of input into computer systems. For these reasons, devices such as portable digital writing surface devices were created. These systems allow users to write as they would traditionally but the writing is automatically digitized via a specialized writing surface. This enables users that have not adapted to traditional keyboard typing for data entry and the like to use systems via this type of technology. Users eventually began using the devices to edit documents and drawings. These markings or “annotations” became part of the digital document in a “fixed” or picture form. Thus, as long as the document remained the same and was not manipulated, the annotated marks remained over the underlying text. However, as can be expected, opening a digital document in different word processors or different screen resolutions causes the document to change in layout and size. This causes the annotations to become disconnected and improperly applied to other areas of the document. This leads to great confusion to the meaning of the marks and severely limits the applicability of digital annotations. A user must feel confident that their editing comments, drawing insertions, and other annotations remain in place so that any user can retrieve the document and interpret the comments the same as the author had intended.